Fuel injection device for internalcombustion engines



July 27, 1948. I E, p PAXMAN 2,445,923

FUEL INJECTION DEVICE FOR INTERNAL-COMBUSTION ENGINES Filed June l26, 1944 A Harney:

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Reference will now be made to the accom- Patented July 27, 194s UNITED STATES PATENT oElcE FUEL INJECTION DEVICE FOR INTERNAL- l COMBUSTION ENGINES Edward Philip rax'mnn, Colchester, England Applinaunnjnne 26,1944, selnl 510.542,176

' 1n Great Britain April ze, 1943 This invention relates to fuel injection devices and while having more particular reference to the fuel injection devices of certain types of internal combustion engines is also applicable to injection devices of the kind used in boiler and other furnaces.

The object of the invention is to provide an vimproved form of valve device applicable to a fuel injector nozzle to enable the construction and manufacture of such nozzles to be considy erably simplified.

l According to the inventiona fuel injection de vice is provided wherein the fuel is admitted -through a nozzle with which co-operates avalve l component comprising a compressible body capable of .being initially set so that the pressure of the injected fuel is utilized in lifting the valve oil` of its seat.

According to the preferred form of the invention the improved fuel injection Ldevice comprises a casing, means for securing said casing in position adjacent a combustion chamber or the like, a valve component in said casing formed of a compressible plastic or other resilient material adaptedto engage a fixed valve seatingand 'to open under pressure due to the incoming fuel and means for setting the panying drawings in which:

Fig. l is a sectional elevation showing one form of the improved fuel injector nozzle, and

- Fig. 2 is a sectional elevation of an alternative form of construction.

Referring rst to Figure l, a fuel injector nozzle s claims. (tcl. rs1-53) h which abuts an annular shoulder i formed withy in the casing a. The outer end of the valve element has a central passage i communicating with radial ports lc situated slightly in advance of the annular shoulder h and communicating with an` annular passage l formed between the valve ele# Vment d and the inner wall of the casing a. The

casing a has a central aperture m at its inner end forming avalve seat in which the steel tip e of the valve-element engages, being held in this Vposition with its annular shoulder h engaging the shoulder i by the flanged end n of an inlet pipe o. This mounting of the valve element enables it to be initially compressed to such a degree that it exerts pressure on the valve seat m equal to the pressure at which the valve should open during operation.

The delivery pipe o is enabled by the construction above-described to enter the devicein a position co-axial with the nozzle and this pipe is secured in position by a nut q which engages a screw-threaded socket in the casing member a whichvmay be-provided externally with a hexagonal portion pto-facilitate its mounting in the cylinder head c. The inner end of the nut q bears against the anged end n of the inlet pipe and pressure at which saidvalve` the pressure necessary to seat the member e on ."the valve seatjmfis obtained -by screwing in the l l*nut q.V If, for example, it is intended that the valve shouldopen at a pressure of .1500 lbs. per

' square inch, the valve element d should be comfor an internal combustion engine comprises a protective casing or sleeve a `of substantially cylindrical-form which is screw threaded at its forward end b to enable it to be mounted in a' cylinder head c in a manner similar lto a sparking plug. Within ,the casing a is mounted an inlet valve element d which is made of a resilient material such as a plastic material of a character capable of being compressed but possessing also a degree of recovery which enables it to act in a manner similar to a spring. The valve element d is of cylindrical form having a substantially conical tip e at its end nearer the combustion chamber f, this tip` being formed of a heateresisting hardened steel and being secured to the valve element by means of a rearwardly extending shank e fitted into a cylindrical socket in the valve element.

The outer endl of the valve element is of enl. larged diameter at g to form an annular shoulder ponent parts are indicated by the same reference l letters, but the casing a, in this instance also contains a cylindrical steel nozzle r which provides at its inner end the valve seating m and at its outer end bears against the shoulder h, on the valve member. In this form of the invention the casinga is formed with cooling ilns s which may be of hexagonal form to facilitate screwing of the casing a into the operative position shown.

For the purpose of making a joint between casing a and the cylinder head c capable of resisting the pressure of the gases in the combustion chamber, it is preferred to employ a washer, which may be of copper, indicated at v in Figs. 1 and 2, which is interposed between the inner end of the nozzle and the end of the recess in which it is mounted. In Fig. 2 there is also shown a protective button t formed of a heatresisting material to screen the face of the nozzle from the effects of combustion and the gases resulting therefrom.

By employing a valve element made of a plastic or other compressible material, the invention enables manufacture to be considerably cheapened and it is especially applicable to small engines as it eliminates the use of a spring and complex port arrangements frequently found in nozzles of the kind described. The construction also enables the fuel delivery connection to be made coaxial with the nozzle.

I claim:

1. A fuel injection device for an internal combustion engine of the compression-ignition type, comprising a casing, a valve seat, formed centrally at the inner end of said casing, a valve component mounted within said casing providing a surrounding annular passage between it and the casing and comprising a substantially cylindrical member composed of solid compressible material, a conical tip composed of heat-resistant material carried by the inner end of said valve component and adapted to engage said seat, a fuel delivery pipe secured to said casing in axial alignment with said valve component, a central inlet passage and radial ports in said valve component through which fuel from said delivery pipe passes to said annular passage and said valve seat, and means for exerting pressure on the outer end of said valve component through said delivery pipe, the tip having an effective area exposed to hydraulic pressure in said annular passage which is larger than the area of said central inlet passage, and the valve component being inherently compressible axially by hydraulic pressure in said annular passage acting on said effective area of the tip to disengage the tip of the valve component from the valve seat.

2. A fuel injection valve comprisingv a casing having a seat therein, a valve component composed of a solid compressible plastic material and embodying an elongated stem having a tip at one end composed of a hardened heat-resistant metal engageable with the seat in the casing and having a central axial fuel inlet passage in its other. A

end, said stem being spaced from the casing to form an annular passage which communicates with the seat in the casing and said fuel inlet passage in the valve component, a fuel delivery pipe disposed coaxially with the valve component and communicating with said fuel inlet passage therein, and means for applying a variable pressure to the fuel delivery pipe to compress axially the stem of the valve component and thereby press the tip o'f said stem against the seat in the casing, the tip having an effective area exposed to hydraulic pressure in said annular passage which is larger than the area of said central inlet passage, and the valve component being inherently compressible axially by hydraulic pressure in said annular passage acting on said effective area of the tip of the stem of the valve component to disengage the tip of the valve component from the valve seat.

3. A fuel injection device for an internal combustion engine of the compression-ignition type, comprising a casing having a valveseat formed centrally at its inner end and an annular shoulder axially spaced outwardly therefrom, a valve component composed of a solid compressible plastic material and embodying an elongated stem having at one end a tip composed of hardened heat-resistant steel engageable with the valve seat and having an annular enlargement at its other end engageable with said annular shoulder of the casing. said stem of the valve component being spaced radially from the casing to form a surrounding annular passage which communicates with the valve seat, and the valve component having a central axially extending inlet passage extending inwardly from its outer end and through said annular enlargement and having radial ports connecting said central passage and surrounding annular passage, a fuel delivery pipe in axial alignment with said valve component and engaging the outer end of said annular enlargement thereon, and. means for applying a variable force-to the fuel delivery pipe to compress axially and preload the valve component and thereby press the tip of the stem against the valve seat, the tip having an effective area exposed to hydraulic pressure in said annular passage which is larger than the area of said central inlet passage, and the valve component being inherently compressible axially by hydraulic pressure in said annular passage acting on said effective area of the tip to disengage the tip of the stem ofthe valve component from the valve seat.

EDWARD PHILIP PAXMAN.

REFERENCES QITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number 

